1072 lines
38 KiB
Rust
1072 lines
38 KiB
Rust
// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use llvm::{self, ValueRef, AttributePlace};
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use base;
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use builder::Builder;
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use common::{ty_fn_sig, C_usize};
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use context::CodegenCx;
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use cabi_x86;
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use cabi_x86_64;
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use cabi_x86_win64;
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use cabi_arm;
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use cabi_aarch64;
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use cabi_powerpc;
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use cabi_powerpc64;
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use cabi_s390x;
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use cabi_mips;
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use cabi_mips64;
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use cabi_asmjs;
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use cabi_msp430;
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use cabi_sparc;
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use cabi_sparc64;
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use cabi_nvptx;
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use cabi_nvptx64;
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use cabi_hexagon;
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use mir::place::PlaceRef;
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use mir::operand::OperandValue;
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use type_::Type;
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use type_of::{LayoutLlvmExt, PointerKind};
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use rustc::ty::{self, Ty};
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use rustc::ty::layout::{self, Align, Size, TyLayout};
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use rustc::ty::layout::{HasDataLayout, LayoutOf};
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use libc::c_uint;
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use std::cmp;
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pub use syntax::abi::Abi;
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pub use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
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#[derive(Clone, Copy, PartialEq, Eq, Debug)]
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pub enum PassMode {
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/// Ignore the argument (useful for empty struct).
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Ignore,
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/// Pass the argument directly.
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Direct(ArgAttributes),
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/// Pass a pair's elements directly in two arguments.
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Pair(ArgAttributes, ArgAttributes),
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/// Pass the argument after casting it, to either
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/// a single uniform or a pair of registers.
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Cast(CastTarget),
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/// Pass the argument indirectly via a hidden pointer.
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Indirect(ArgAttributes),
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}
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// Hack to disable non_upper_case_globals only for the bitflags! and not for the rest
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// of this module
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pub use self::attr_impl::ArgAttribute;
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#[allow(non_upper_case_globals)]
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#[allow(unused)]
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mod attr_impl {
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// The subset of llvm::Attribute needed for arguments, packed into a bitfield.
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bitflags! {
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#[derive(Default)]
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pub struct ArgAttribute: u16 {
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const ByVal = 1 << 0;
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const NoAlias = 1 << 1;
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const NoCapture = 1 << 2;
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const NonNull = 1 << 3;
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const ReadOnly = 1 << 4;
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const SExt = 1 << 5;
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const StructRet = 1 << 6;
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const ZExt = 1 << 7;
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const InReg = 1 << 8;
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}
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}
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}
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macro_rules! for_each_kind {
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($flags: ident, $f: ident, $($kind: ident),+) => ({
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$(if $flags.contains(ArgAttribute::$kind) { $f(llvm::Attribute::$kind) })+
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})
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}
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impl ArgAttribute {
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fn for_each_kind<F>(&self, mut f: F) where F: FnMut(llvm::Attribute) {
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for_each_kind!(self, f,
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ByVal, NoAlias, NoCapture, NonNull, ReadOnly, SExt, StructRet, ZExt, InReg)
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}
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}
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/// A compact representation of LLVM attributes (at least those relevant for this module)
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/// that can be manipulated without interacting with LLVM's Attribute machinery.
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub struct ArgAttributes {
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regular: ArgAttribute,
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pointee_size: Size,
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pointee_align: Option<Align>
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}
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impl ArgAttributes {
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fn new() -> Self {
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ArgAttributes {
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regular: ArgAttribute::default(),
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pointee_size: Size::from_bytes(0),
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pointee_align: None,
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}
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}
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pub fn set(&mut self, attr: ArgAttribute) -> &mut Self {
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self.regular = self.regular | attr;
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self
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}
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pub fn contains(&self, attr: ArgAttribute) -> bool {
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self.regular.contains(attr)
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}
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pub fn apply_llfn(&self, idx: AttributePlace, llfn: ValueRef) {
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let mut regular = self.regular;
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unsafe {
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let deref = self.pointee_size.bytes();
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if deref != 0 {
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if regular.contains(ArgAttribute::NonNull) {
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llvm::LLVMRustAddDereferenceableAttr(llfn,
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idx.as_uint(),
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deref);
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} else {
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llvm::LLVMRustAddDereferenceableOrNullAttr(llfn,
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idx.as_uint(),
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deref);
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}
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regular -= ArgAttribute::NonNull;
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}
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if let Some(align) = self.pointee_align {
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llvm::LLVMRustAddAlignmentAttr(llfn,
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idx.as_uint(),
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align.abi() as u32);
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}
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regular.for_each_kind(|attr| attr.apply_llfn(idx, llfn));
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}
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}
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pub fn apply_callsite(&self, idx: AttributePlace, callsite: ValueRef) {
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let mut regular = self.regular;
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unsafe {
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let deref = self.pointee_size.bytes();
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if deref != 0 {
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if regular.contains(ArgAttribute::NonNull) {
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llvm::LLVMRustAddDereferenceableCallSiteAttr(callsite,
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idx.as_uint(),
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deref);
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} else {
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llvm::LLVMRustAddDereferenceableOrNullCallSiteAttr(callsite,
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idx.as_uint(),
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deref);
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}
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regular -= ArgAttribute::NonNull;
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}
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if let Some(align) = self.pointee_align {
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llvm::LLVMRustAddAlignmentCallSiteAttr(callsite,
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idx.as_uint(),
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align.abi() as u32);
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}
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regular.for_each_kind(|attr| attr.apply_callsite(idx, callsite));
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}
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}
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub enum RegKind {
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Integer,
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Float,
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Vector
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub struct Reg {
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pub kind: RegKind,
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pub size: Size,
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}
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macro_rules! reg_ctor {
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($name:ident, $kind:ident, $bits:expr) => {
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pub fn $name() -> Reg {
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Reg {
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kind: RegKind::$kind,
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size: Size::from_bits($bits)
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}
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}
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}
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}
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impl Reg {
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reg_ctor!(i8, Integer, 8);
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reg_ctor!(i16, Integer, 16);
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reg_ctor!(i32, Integer, 32);
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reg_ctor!(i64, Integer, 64);
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reg_ctor!(f32, Float, 32);
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reg_ctor!(f64, Float, 64);
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}
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impl Reg {
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pub fn align(&self, cx: &CodegenCx) -> Align {
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let dl = cx.data_layout();
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match self.kind {
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RegKind::Integer => {
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match self.size.bits() {
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1 => dl.i1_align,
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2...8 => dl.i8_align,
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9...16 => dl.i16_align,
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17...32 => dl.i32_align,
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33...64 => dl.i64_align,
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65...128 => dl.i128_align,
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_ => bug!("unsupported integer: {:?}", self)
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}
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}
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RegKind::Float => {
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match self.size.bits() {
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32 => dl.f32_align,
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64 => dl.f64_align,
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_ => bug!("unsupported float: {:?}", self)
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}
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}
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RegKind::Vector => dl.vector_align(self.size)
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}
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}
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pub fn llvm_type(&self, cx: &CodegenCx) -> Type {
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match self.kind {
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RegKind::Integer => Type::ix(cx, self.size.bits()),
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RegKind::Float => {
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match self.size.bits() {
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32 => Type::f32(cx),
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64 => Type::f64(cx),
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_ => bug!("unsupported float: {:?}", self)
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}
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}
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RegKind::Vector => {
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Type::vector(&Type::i8(cx), self.size.bytes())
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}
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}
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}
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}
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/// An argument passed entirely registers with the
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/// same kind (e.g. HFA / HVA on PPC64 and AArch64).
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#[derive(Clone, Copy, PartialEq, Eq, Debug)]
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pub struct Uniform {
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pub unit: Reg,
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/// The total size of the argument, which can be:
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/// * equal to `unit.size` (one scalar/vector)
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/// * a multiple of `unit.size` (an array of scalar/vectors)
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/// * if `unit.kind` is `Integer`, the last element
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/// can be shorter, i.e. `{ i64, i64, i32 }` for
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/// 64-bit integers with a total size of 20 bytes
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pub total: Size,
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}
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impl From<Reg> for Uniform {
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fn from(unit: Reg) -> Uniform {
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Uniform {
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unit,
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total: unit.size
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}
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}
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}
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impl Uniform {
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pub fn align(&self, cx: &CodegenCx) -> Align {
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self.unit.align(cx)
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}
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}
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pub trait LayoutExt<'tcx> {
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fn is_aggregate(&self) -> bool;
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fn homogeneous_aggregate<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> Option<Reg>;
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}
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impl<'tcx> LayoutExt<'tcx> for TyLayout<'tcx> {
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fn is_aggregate(&self) -> bool {
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match self.abi {
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layout::Abi::Uninhabited |
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layout::Abi::Scalar(_) |
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layout::Abi::Vector { .. } => false,
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layout::Abi::ScalarPair(..) |
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layout::Abi::Aggregate { .. } => true
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}
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}
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fn homogeneous_aggregate<'a>(&self, cx: &CodegenCx<'a, 'tcx>) -> Option<Reg> {
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match self.abi {
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layout::Abi::Uninhabited => None,
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// The primitive for this algorithm.
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layout::Abi::Scalar(ref scalar) => {
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let kind = match scalar.value {
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layout::Int(..) |
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layout::Pointer => RegKind::Integer,
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layout::F32 |
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layout::F64 => RegKind::Float
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};
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Some(Reg {
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kind,
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size: self.size
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})
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}
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layout::Abi::Vector { .. } => {
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Some(Reg {
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kind: RegKind::Vector,
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size: self.size
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})
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}
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layout::Abi::ScalarPair(..) |
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layout::Abi::Aggregate { .. } => {
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let mut total = Size::from_bytes(0);
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let mut result = None;
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let is_union = match self.fields {
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layout::FieldPlacement::Array { count, .. } => {
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if count > 0 {
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return self.field(cx, 0).homogeneous_aggregate(cx);
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} else {
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return None;
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}
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}
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layout::FieldPlacement::Union(_) => true,
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layout::FieldPlacement::Arbitrary { .. } => false
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};
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for i in 0..self.fields.count() {
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if !is_union && total != self.fields.offset(i) {
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return None;
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}
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let field = self.field(cx, i);
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match (result, field.homogeneous_aggregate(cx)) {
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// The field itself must be a homogeneous aggregate.
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(_, None) => return None,
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// If this is the first field, record the unit.
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(None, Some(unit)) => {
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result = Some(unit);
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}
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// For all following fields, the unit must be the same.
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(Some(prev_unit), Some(unit)) => {
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if prev_unit != unit {
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return None;
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}
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}
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}
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// Keep track of the offset (without padding).
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let size = field.size;
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if is_union {
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total = cmp::max(total, size);
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} else {
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total += size;
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}
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}
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// There needs to be no padding.
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if total != self.size {
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None
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} else {
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result
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}
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}
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}
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}
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}
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#[derive(Clone, Copy, PartialEq, Eq, Debug)]
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pub struct CastTarget {
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pub prefix: [Option<RegKind>; 8],
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pub prefix_chunk: Size,
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pub rest: Uniform,
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}
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impl From<Reg> for CastTarget {
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fn from(unit: Reg) -> CastTarget {
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CastTarget::from(Uniform::from(unit))
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}
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}
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impl From<Uniform> for CastTarget {
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fn from(uniform: Uniform) -> CastTarget {
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CastTarget {
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prefix: [None; 8],
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prefix_chunk: Size::from_bytes(0),
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rest: uniform
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}
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}
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}
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impl CastTarget {
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pub fn pair(a: Reg, b: Reg) -> CastTarget {
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CastTarget {
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prefix: [Some(a.kind), None, None, None, None, None, None, None],
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prefix_chunk: a.size,
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rest: Uniform::from(b)
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}
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}
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pub fn size(&self, cx: &CodegenCx) -> Size {
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(self.prefix_chunk * self.prefix.iter().filter(|x| x.is_some()).count() as u64)
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.abi_align(self.rest.align(cx)) + self.rest.total
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}
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pub fn align(&self, cx: &CodegenCx) -> Align {
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self.prefix.iter()
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.filter_map(|x| x.map(|kind| Reg { kind: kind, size: self.prefix_chunk }.align(cx)))
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.fold(cx.data_layout().aggregate_align.max(self.rest.align(cx)),
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|acc, align| acc.max(align))
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}
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pub fn llvm_type(&self, cx: &CodegenCx) -> Type {
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let rest_ll_unit = self.rest.unit.llvm_type(cx);
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let rest_count = self.rest.total.bytes() / self.rest.unit.size.bytes();
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let rem_bytes = self.rest.total.bytes() % self.rest.unit.size.bytes();
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if self.prefix.iter().all(|x| x.is_none()) {
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// Simplify to a single unit when there is no prefix and size <= unit size
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if self.rest.total <= self.rest.unit.size {
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return rest_ll_unit;
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}
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// Simplify to array when all chunks are the same size and type
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if rem_bytes == 0 {
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return Type::array(&rest_ll_unit, rest_count);
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}
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}
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// Create list of fields in the main structure
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let mut args: Vec<_> =
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self.prefix.iter().flat_map(|option_kind| option_kind.map(
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|kind| Reg { kind: kind, size: self.prefix_chunk }.llvm_type(cx)))
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.chain((0..rest_count).map(|_| rest_ll_unit))
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.collect();
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// Append final integer
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if rem_bytes != 0 {
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// Only integers can be really split further.
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assert_eq!(self.rest.unit.kind, RegKind::Integer);
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args.push(Type::ix(cx, rem_bytes * 8));
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}
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Type::struct_(cx, &args, false)
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}
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}
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/// Information about how to pass an argument to,
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/// or return a value from, a function, under some ABI.
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#[derive(Debug)]
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pub struct ArgType<'tcx> {
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pub layout: TyLayout<'tcx>,
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/// Dummy argument, which is emitted before the real argument.
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pub pad: Option<Reg>,
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pub mode: PassMode,
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}
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impl<'a, 'tcx> ArgType<'tcx> {
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fn new(layout: TyLayout<'tcx>) -> ArgType<'tcx> {
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ArgType {
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layout,
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pad: None,
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mode: PassMode::Direct(ArgAttributes::new()),
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}
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}
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pub fn make_indirect(&mut self) {
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assert_eq!(self.mode, PassMode::Direct(ArgAttributes::new()));
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// Start with fresh attributes for the pointer.
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let mut attrs = ArgAttributes::new();
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// For non-immediate arguments the callee gets its own copy of
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// the value on the stack, so there are no aliases. It's also
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// program-invisible so can't possibly capture
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attrs.set(ArgAttribute::NoAlias)
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.set(ArgAttribute::NoCapture)
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.set(ArgAttribute::NonNull);
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attrs.pointee_size = self.layout.size;
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// FIXME(eddyb) We should be doing this, but at least on
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// i686-pc-windows-msvc, it results in wrong stack offsets.
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// attrs.pointee_align = Some(self.layout.align);
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self.mode = PassMode::Indirect(attrs);
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}
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pub fn make_indirect_byval(&mut self) {
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self.make_indirect();
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match self.mode {
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PassMode::Indirect(ref mut attrs) => {
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attrs.set(ArgAttribute::ByVal);
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}
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_ => bug!()
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}
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}
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pub fn extend_integer_width_to(&mut self, bits: u64) {
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// Only integers have signedness
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if let layout::Abi::Scalar(ref scalar) = self.layout.abi {
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if let layout::Int(i, signed) = scalar.value {
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if i.size().bits() < bits {
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if let PassMode::Direct(ref mut attrs) = self.mode {
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attrs.set(if signed {
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ArgAttribute::SExt
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} else {
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ArgAttribute::ZExt
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});
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}
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}
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}
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}
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}
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|
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pub fn cast_to<T: Into<CastTarget>>(&mut self, target: T) {
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assert_eq!(self.mode, PassMode::Direct(ArgAttributes::new()));
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self.mode = PassMode::Cast(target.into());
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}
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pub fn pad_with(&mut self, reg: Reg) {
|
|
self.pad = Some(reg);
|
|
}
|
|
|
|
pub fn is_indirect(&self) -> bool {
|
|
match self.mode {
|
|
PassMode::Indirect(_) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
pub fn is_ignore(&self) -> bool {
|
|
self.mode == PassMode::Ignore
|
|
}
|
|
|
|
/// Get the LLVM type for a place of the original Rust type of
|
|
/// this argument/return, i.e. the result of `type_of::type_of`.
|
|
pub fn memory_ty(&self, cx: &CodegenCx<'a, 'tcx>) -> Type {
|
|
self.layout.llvm_type(cx)
|
|
}
|
|
|
|
/// Store a direct/indirect value described by this ArgType into a
|
|
/// place for the original Rust type of this argument/return.
|
|
/// Can be used for both storing formal arguments into Rust variables
|
|
/// or results of call/invoke instructions into their destinations.
|
|
pub fn store(&self, bx: &Builder<'a, 'tcx>, val: ValueRef, dst: PlaceRef<'tcx>) {
|
|
if self.is_ignore() {
|
|
return;
|
|
}
|
|
let cx = bx.cx;
|
|
if self.is_indirect() {
|
|
OperandValue::Ref(val, self.layout.align).store(bx, dst)
|
|
} else if let PassMode::Cast(cast) = self.mode {
|
|
// FIXME(eddyb): Figure out when the simpler Store is safe, clang
|
|
// uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
|
|
let can_store_through_cast_ptr = false;
|
|
if can_store_through_cast_ptr {
|
|
let cast_dst = bx.pointercast(dst.llval, cast.llvm_type(cx).ptr_to());
|
|
bx.store(val, cast_dst, self.layout.align);
|
|
} else {
|
|
// The actual return type is a struct, but the ABI
|
|
// adaptation code has cast it into some scalar type. The
|
|
// code that follows is the only reliable way I have
|
|
// found to do a transform like i64 -> {i32,i32}.
|
|
// Basically we dump the data onto the stack then memcpy it.
|
|
//
|
|
// Other approaches I tried:
|
|
// - Casting rust ret pointer to the foreign type and using Store
|
|
// is (a) unsafe if size of foreign type > size of rust type and
|
|
// (b) runs afoul of strict aliasing rules, yielding invalid
|
|
// assembly under -O (specifically, the store gets removed).
|
|
// - Truncating foreign type to correct integral type and then
|
|
// bitcasting to the struct type yields invalid cast errors.
|
|
|
|
// We instead thus allocate some scratch space...
|
|
let scratch_size = cast.size(cx);
|
|
let scratch_align = cast.align(cx);
|
|
let llscratch = bx.alloca(cast.llvm_type(cx), "abi_cast", scratch_align);
|
|
bx.lifetime_start(llscratch, scratch_size);
|
|
|
|
// ...where we first store the value...
|
|
bx.store(val, llscratch, scratch_align);
|
|
|
|
// ...and then memcpy it to the intended destination.
|
|
base::call_memcpy(bx,
|
|
bx.pointercast(dst.llval, Type::i8p(cx)),
|
|
bx.pointercast(llscratch, Type::i8p(cx)),
|
|
C_usize(cx, self.layout.size.bytes()),
|
|
self.layout.align.min(scratch_align));
|
|
|
|
bx.lifetime_end(llscratch, scratch_size);
|
|
}
|
|
} else {
|
|
OperandValue::Immediate(val).store(bx, dst);
|
|
}
|
|
}
|
|
|
|
pub fn store_fn_arg(&self, bx: &Builder<'a, 'tcx>, idx: &mut usize, dst: PlaceRef<'tcx>) {
|
|
let mut next = || {
|
|
let val = llvm::get_param(bx.llfn(), *idx as c_uint);
|
|
*idx += 1;
|
|
val
|
|
};
|
|
match self.mode {
|
|
PassMode::Ignore => {},
|
|
PassMode::Pair(..) => {
|
|
OperandValue::Pair(next(), next()).store(bx, dst);
|
|
}
|
|
PassMode::Direct(_) | PassMode::Indirect(_) | PassMode::Cast(_) => {
|
|
self.store(bx, next(), dst);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Metadata describing how the arguments to a native function
|
|
/// should be passed in order to respect the native ABI.
|
|
///
|
|
/// I will do my best to describe this structure, but these
|
|
/// comments are reverse-engineered and may be inaccurate. -NDM
|
|
#[derive(Debug)]
|
|
pub struct FnType<'tcx> {
|
|
/// The LLVM types of each argument.
|
|
pub args: Vec<ArgType<'tcx>>,
|
|
|
|
/// LLVM return type.
|
|
pub ret: ArgType<'tcx>,
|
|
|
|
pub variadic: bool,
|
|
|
|
pub cconv: llvm::CallConv
|
|
}
|
|
|
|
impl<'a, 'tcx> FnType<'tcx> {
|
|
pub fn of_instance(cx: &CodegenCx<'a, 'tcx>, instance: &ty::Instance<'tcx>)
|
|
-> Self {
|
|
let fn_ty = instance.ty(cx.tcx);
|
|
let sig = ty_fn_sig(cx, fn_ty);
|
|
let sig = cx.tcx.erase_late_bound_regions_and_normalize(&sig);
|
|
FnType::new(cx, sig, &[])
|
|
}
|
|
|
|
pub fn new(cx: &CodegenCx<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
let mut fn_ty = FnType::unadjusted(cx, sig, extra_args);
|
|
fn_ty.adjust_for_abi(cx, sig.abi);
|
|
fn_ty
|
|
}
|
|
|
|
pub fn new_vtable(cx: &CodegenCx<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
let mut fn_ty = FnType::unadjusted(cx, sig, extra_args);
|
|
// Don't pass the vtable, it's not an argument of the virtual fn.
|
|
{
|
|
let self_arg = &mut fn_ty.args[0];
|
|
match self_arg.mode {
|
|
PassMode::Pair(data_ptr, _) => {
|
|
self_arg.mode = PassMode::Direct(data_ptr);
|
|
}
|
|
_ => bug!("FnType::new_vtable: non-pair self {:?}", self_arg)
|
|
}
|
|
|
|
let pointee = self_arg.layout.ty.builtin_deref(true)
|
|
.unwrap_or_else(|| {
|
|
bug!("FnType::new_vtable: non-pointer self {:?}", self_arg)
|
|
}).ty;
|
|
let fat_ptr_ty = cx.tcx.mk_mut_ptr(pointee);
|
|
self_arg.layout = cx.layout_of(fat_ptr_ty).field(cx, 0);
|
|
}
|
|
fn_ty.adjust_for_abi(cx, sig.abi);
|
|
fn_ty
|
|
}
|
|
|
|
pub fn unadjusted(cx: &CodegenCx<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
debug!("FnType::unadjusted({:?}, {:?})", sig, extra_args);
|
|
|
|
use self::Abi::*;
|
|
let cconv = match cx.sess().target.target.adjust_abi(sig.abi) {
|
|
RustIntrinsic | PlatformIntrinsic |
|
|
Rust | RustCall => llvm::CCallConv,
|
|
|
|
// It's the ABI's job to select this, not us.
|
|
System => bug!("system abi should be selected elsewhere"),
|
|
|
|
Stdcall => llvm::X86StdcallCallConv,
|
|
Fastcall => llvm::X86FastcallCallConv,
|
|
Vectorcall => llvm::X86_VectorCall,
|
|
Thiscall => llvm::X86_ThisCall,
|
|
C => llvm::CCallConv,
|
|
Unadjusted => llvm::CCallConv,
|
|
Win64 => llvm::X86_64_Win64,
|
|
SysV64 => llvm::X86_64_SysV,
|
|
Aapcs => llvm::ArmAapcsCallConv,
|
|
PtxKernel => llvm::PtxKernel,
|
|
Msp430Interrupt => llvm::Msp430Intr,
|
|
X86Interrupt => llvm::X86_Intr,
|
|
|
|
// These API constants ought to be more specific...
|
|
Cdecl => llvm::CCallConv,
|
|
};
|
|
|
|
let mut inputs = sig.inputs();
|
|
let extra_args = if sig.abi == RustCall {
|
|
assert!(!sig.variadic && extra_args.is_empty());
|
|
|
|
match sig.inputs().last().unwrap().sty {
|
|
ty::TyTuple(ref tupled_arguments, _) => {
|
|
inputs = &sig.inputs()[0..sig.inputs().len() - 1];
|
|
tupled_arguments
|
|
}
|
|
_ => {
|
|
bug!("argument to function with \"rust-call\" ABI \
|
|
is not a tuple");
|
|
}
|
|
}
|
|
} else {
|
|
assert!(sig.variadic || extra_args.is_empty());
|
|
extra_args
|
|
};
|
|
|
|
let target = &cx.sess().target.target;
|
|
let win_x64_gnu = target.target_os == "windows"
|
|
&& target.arch == "x86_64"
|
|
&& target.target_env == "gnu";
|
|
let linux_s390x = target.target_os == "linux"
|
|
&& target.arch == "s390x"
|
|
&& target.target_env == "gnu";
|
|
let rust_abi = match sig.abi {
|
|
RustIntrinsic | PlatformIntrinsic | Rust | RustCall => true,
|
|
_ => false
|
|
};
|
|
|
|
// Handle safe Rust thin and fat pointers.
|
|
let adjust_for_rust_scalar = |attrs: &mut ArgAttributes,
|
|
scalar: &layout::Scalar,
|
|
layout: TyLayout<'tcx>,
|
|
offset: Size,
|
|
is_return: bool| {
|
|
// Booleans are always an i1 that needs to be zero-extended.
|
|
if scalar.is_bool() {
|
|
attrs.set(ArgAttribute::ZExt);
|
|
return;
|
|
}
|
|
|
|
// Only pointer types handled below.
|
|
if scalar.value != layout::Pointer {
|
|
return;
|
|
}
|
|
|
|
if scalar.valid_range.start < scalar.valid_range.end {
|
|
if scalar.valid_range.start > 0 {
|
|
attrs.set(ArgAttribute::NonNull);
|
|
}
|
|
}
|
|
|
|
if let Some(pointee) = layout.pointee_info_at(cx, offset) {
|
|
if let Some(kind) = pointee.safe {
|
|
attrs.pointee_size = pointee.size;
|
|
attrs.pointee_align = Some(pointee.align);
|
|
|
|
// HACK(eddyb) LLVM inserts `llvm.assume` calls when inlining functions
|
|
// with align attributes, and those calls later block optimizations.
|
|
if !is_return {
|
|
attrs.pointee_align = None;
|
|
}
|
|
|
|
// `Box` pointer parameters never alias because ownership is transferred
|
|
// `&mut` pointer parameters never alias other parameters,
|
|
// or mutable global data
|
|
//
|
|
// `&T` where `T` contains no `UnsafeCell<U>` is immutable,
|
|
// and can be marked as both `readonly` and `noalias`, as
|
|
// LLVM's definition of `noalias` is based solely on memory
|
|
// dependencies rather than pointer equality
|
|
let no_alias = match kind {
|
|
PointerKind::Shared => false,
|
|
PointerKind::UniqueOwned => true,
|
|
PointerKind::Frozen |
|
|
PointerKind::UniqueBorrowed => !is_return
|
|
};
|
|
if no_alias {
|
|
attrs.set(ArgAttribute::NoAlias);
|
|
}
|
|
|
|
if kind == PointerKind::Frozen && !is_return {
|
|
attrs.set(ArgAttribute::ReadOnly);
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
let arg_of = |ty: Ty<'tcx>, is_return: bool| {
|
|
let mut arg = ArgType::new(cx.layout_of(ty));
|
|
if arg.layout.is_zst() {
|
|
// For some forsaken reason, x86_64-pc-windows-gnu
|
|
// doesn't ignore zero-sized struct arguments.
|
|
// The same is true for s390x-unknown-linux-gnu.
|
|
if is_return || rust_abi || (!win_x64_gnu && !linux_s390x) {
|
|
arg.mode = PassMode::Ignore;
|
|
}
|
|
}
|
|
|
|
// FIXME(eddyb) other ABIs don't have logic for scalar pairs.
|
|
if !is_return && rust_abi {
|
|
if let layout::Abi::ScalarPair(ref a, ref b) = arg.layout.abi {
|
|
let mut a_attrs = ArgAttributes::new();
|
|
let mut b_attrs = ArgAttributes::new();
|
|
adjust_for_rust_scalar(&mut a_attrs,
|
|
a,
|
|
arg.layout,
|
|
Size::from_bytes(0),
|
|
false);
|
|
adjust_for_rust_scalar(&mut b_attrs,
|
|
b,
|
|
arg.layout,
|
|
a.value.size(cx).abi_align(b.value.align(cx)),
|
|
false);
|
|
arg.mode = PassMode::Pair(a_attrs, b_attrs);
|
|
return arg;
|
|
}
|
|
}
|
|
|
|
if let layout::Abi::Scalar(ref scalar) = arg.layout.abi {
|
|
if let PassMode::Direct(ref mut attrs) = arg.mode {
|
|
adjust_for_rust_scalar(attrs,
|
|
scalar,
|
|
arg.layout,
|
|
Size::from_bytes(0),
|
|
is_return);
|
|
}
|
|
}
|
|
|
|
arg
|
|
};
|
|
|
|
FnType {
|
|
ret: arg_of(sig.output(), true),
|
|
args: inputs.iter().chain(extra_args.iter()).map(|ty| {
|
|
arg_of(ty, false)
|
|
}).collect(),
|
|
variadic: sig.variadic,
|
|
cconv,
|
|
}
|
|
}
|
|
|
|
fn adjust_for_abi(&mut self,
|
|
cx: &CodegenCx<'a, 'tcx>,
|
|
abi: Abi) {
|
|
if abi == Abi::Unadjusted { return }
|
|
|
|
if abi == Abi::Rust || abi == Abi::RustCall ||
|
|
abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic {
|
|
let fixup = |arg: &mut ArgType<'tcx>| {
|
|
if arg.is_ignore() { return; }
|
|
|
|
match arg.layout.abi {
|
|
layout::Abi::Aggregate { .. } => {}
|
|
|
|
// This is a fun case! The gist of what this is doing is
|
|
// that we want callers and callees to always agree on the
|
|
// ABI of how they pass SIMD arguments. If we were to *not*
|
|
// make these arguments indirect then they'd be immediates
|
|
// in LLVM, which means that they'd used whatever the
|
|
// appropriate ABI is for the callee and the caller. That
|
|
// means, for example, if the caller doesn't have AVX
|
|
// enabled but the callee does, then passing an AVX argument
|
|
// across this boundary would cause corrupt data to show up.
|
|
//
|
|
// This problem is fixed by unconditionally passing SIMD
|
|
// arguments through memory between callers and callees
|
|
// which should get them all to agree on ABI regardless of
|
|
// target feature sets. Some more information about this
|
|
// issue can be found in #44367.
|
|
//
|
|
// Note that the platform intrinsic ABI is exempt here as
|
|
// that's how we connect up to LLVM and it's unstable
|
|
// anyway, we control all calls to it in libstd.
|
|
layout::Abi::Vector { .. } if abi != Abi::PlatformIntrinsic => {
|
|
arg.make_indirect();
|
|
return
|
|
}
|
|
|
|
_ => return
|
|
}
|
|
|
|
let size = arg.layout.size;
|
|
if size > layout::Pointer.size(cx) {
|
|
arg.make_indirect();
|
|
} else {
|
|
// We want to pass small aggregates as immediates, but using
|
|
// a LLVM aggregate type for this leads to bad optimizations,
|
|
// so we pick an appropriately sized integer type instead.
|
|
arg.cast_to(Reg {
|
|
kind: RegKind::Integer,
|
|
size
|
|
});
|
|
}
|
|
};
|
|
fixup(&mut self.ret);
|
|
for arg in &mut self.args {
|
|
fixup(arg);
|
|
}
|
|
if let PassMode::Indirect(ref mut attrs) = self.ret.mode {
|
|
attrs.set(ArgAttribute::StructRet);
|
|
}
|
|
return;
|
|
}
|
|
|
|
match &cx.sess().target.target.arch[..] {
|
|
"x86" => {
|
|
let flavor = if abi == Abi::Fastcall {
|
|
cabi_x86::Flavor::Fastcall
|
|
} else {
|
|
cabi_x86::Flavor::General
|
|
};
|
|
cabi_x86::compute_abi_info(cx, self, flavor);
|
|
},
|
|
"x86_64" => if abi == Abi::SysV64 {
|
|
cabi_x86_64::compute_abi_info(cx, self);
|
|
} else if abi == Abi::Win64 || cx.sess().target.target.options.is_like_windows {
|
|
cabi_x86_win64::compute_abi_info(self);
|
|
} else {
|
|
cabi_x86_64::compute_abi_info(cx, self);
|
|
},
|
|
"aarch64" => cabi_aarch64::compute_abi_info(cx, self),
|
|
"arm" => cabi_arm::compute_abi_info(cx, self),
|
|
"mips" => cabi_mips::compute_abi_info(cx, self),
|
|
"mips64" => cabi_mips64::compute_abi_info(cx, self),
|
|
"powerpc" => cabi_powerpc::compute_abi_info(cx, self),
|
|
"powerpc64" => cabi_powerpc64::compute_abi_info(cx, self),
|
|
"s390x" => cabi_s390x::compute_abi_info(cx, self),
|
|
"asmjs" => cabi_asmjs::compute_abi_info(cx, self),
|
|
"wasm32" => cabi_asmjs::compute_abi_info(cx, self),
|
|
"msp430" => cabi_msp430::compute_abi_info(self),
|
|
"sparc" => cabi_sparc::compute_abi_info(cx, self),
|
|
"sparc64" => cabi_sparc64::compute_abi_info(cx, self),
|
|
"nvptx" => cabi_nvptx::compute_abi_info(self),
|
|
"nvptx64" => cabi_nvptx64::compute_abi_info(self),
|
|
"hexagon" => cabi_hexagon::compute_abi_info(self),
|
|
a => cx.sess().fatal(&format!("unrecognized arch \"{}\" in target specification", a))
|
|
}
|
|
|
|
if let PassMode::Indirect(ref mut attrs) = self.ret.mode {
|
|
attrs.set(ArgAttribute::StructRet);
|
|
}
|
|
}
|
|
|
|
pub fn llvm_type(&self, cx: &CodegenCx<'a, 'tcx>) -> Type {
|
|
let mut llargument_tys = Vec::new();
|
|
|
|
let llreturn_ty = match self.ret.mode {
|
|
PassMode::Ignore => Type::void(cx),
|
|
PassMode::Direct(_) | PassMode::Pair(..) => {
|
|
self.ret.layout.immediate_llvm_type(cx)
|
|
}
|
|
PassMode::Cast(cast) => cast.llvm_type(cx),
|
|
PassMode::Indirect(_) => {
|
|
llargument_tys.push(self.ret.memory_ty(cx).ptr_to());
|
|
Type::void(cx)
|
|
}
|
|
};
|
|
|
|
for arg in &self.args {
|
|
// add padding
|
|
if let Some(ty) = arg.pad {
|
|
llargument_tys.push(ty.llvm_type(cx));
|
|
}
|
|
|
|
let llarg_ty = match arg.mode {
|
|
PassMode::Ignore => continue,
|
|
PassMode::Direct(_) => arg.layout.immediate_llvm_type(cx),
|
|
PassMode::Pair(..) => {
|
|
llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 0));
|
|
llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 1));
|
|
continue;
|
|
}
|
|
PassMode::Cast(cast) => cast.llvm_type(cx),
|
|
PassMode::Indirect(_) => arg.memory_ty(cx).ptr_to(),
|
|
};
|
|
llargument_tys.push(llarg_ty);
|
|
}
|
|
|
|
if self.variadic {
|
|
Type::variadic_func(&llargument_tys, &llreturn_ty)
|
|
} else {
|
|
Type::func(&llargument_tys, &llreturn_ty)
|
|
}
|
|
}
|
|
|
|
pub fn apply_attrs_llfn(&self, llfn: ValueRef) {
|
|
let mut i = 0;
|
|
let mut apply = |attrs: &ArgAttributes| {
|
|
attrs.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
|
|
i += 1;
|
|
};
|
|
match self.ret.mode {
|
|
PassMode::Direct(ref attrs) => {
|
|
attrs.apply_llfn(llvm::AttributePlace::ReturnValue, llfn);
|
|
}
|
|
PassMode::Indirect(ref attrs) => apply(attrs),
|
|
_ => {}
|
|
}
|
|
for arg in &self.args {
|
|
if arg.pad.is_some() {
|
|
apply(&ArgAttributes::new());
|
|
}
|
|
match arg.mode {
|
|
PassMode::Ignore => {}
|
|
PassMode::Direct(ref attrs) |
|
|
PassMode::Indirect(ref attrs) => apply(attrs),
|
|
PassMode::Pair(ref a, ref b) => {
|
|
apply(a);
|
|
apply(b);
|
|
}
|
|
PassMode::Cast(_) => apply(&ArgAttributes::new()),
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn apply_attrs_callsite(&self, callsite: ValueRef) {
|
|
let mut i = 0;
|
|
let mut apply = |attrs: &ArgAttributes| {
|
|
attrs.apply_callsite(llvm::AttributePlace::Argument(i), callsite);
|
|
i += 1;
|
|
};
|
|
match self.ret.mode {
|
|
PassMode::Direct(ref attrs) => {
|
|
attrs.apply_callsite(llvm::AttributePlace::ReturnValue, callsite);
|
|
}
|
|
PassMode::Indirect(ref attrs) => apply(attrs),
|
|
_ => {}
|
|
}
|
|
for arg in &self.args {
|
|
if arg.pad.is_some() {
|
|
apply(&ArgAttributes::new());
|
|
}
|
|
match arg.mode {
|
|
PassMode::Ignore => {}
|
|
PassMode::Direct(ref attrs) |
|
|
PassMode::Indirect(ref attrs) => apply(attrs),
|
|
PassMode::Pair(ref a, ref b) => {
|
|
apply(a);
|
|
apply(b);
|
|
}
|
|
PassMode::Cast(_) => apply(&ArgAttributes::new()),
|
|
}
|
|
}
|
|
|
|
if self.cconv != llvm::CCallConv {
|
|
llvm::SetInstructionCallConv(callsite, self.cconv);
|
|
}
|
|
}
|
|
}
|